2015 Preview: ATP No. 5, Kei Nishikori

One of the most unassuming players in the game, Nishikori’s on-court persona could be said to resemble a comic-strip character: Baseball cap, baggy shorts and feet that somehow look too large. But don’t be fooled—the 24-year-old is lethal with a racquet in his hand, as he proved throughout a breakout 2014 season.

Nishikori burst out of the blocks, winning Memphis, reaching the semifinals of the Miami Masters (before withdrawing), and capturing another title in Barcelona. That launched a 14-match winning streak, halted when Nishikori retired with a bad back while leading Rafael Nadal—on clay—in the Madrid final.

Nishikori shook off his latest ailment and saved his best tennis for the U.S. Open, where he outlasted Milos Raonic, Stan Wawrinka, and Novak Djokovic to reach his first career Grand Slam final. If the Japanese star’s health ever equals his consistency on court, expect even greater achievements.

With his youth, excellent footwork and flat, laser-like groundstrokes, Nishikori compensates more than adequately for his relatively small stature. He’s a tough competitor who could establish himself in the upper reaches of the Top 10 for good if he continues to play on or inside the baseline, and keeps finding winning angles like he did last year.

Nishikori has a history of injury, and he hasn't proven capable of playing with pain the way some of his rivals do. The amount of wear and tear he endures, combined with his modest physique and punishing style, means that Nishikori can expect to face more physical challenges. If he capitulates to them, or plays less aggressively than last year, he could get into trouble.

Given his rock-star status in Japan, Nishikori will have to avoid resting on the laurels he earned in 2014. The odds on that happening are slim, though, because he’s been immersed in the performance culture that exists at the IMG Academy Bollettieri Tennis Program since he was 14.

For more 2015 season previews, click here.